Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000352.6(ABCC8):c.3124_3126delACCinsCAGCCAGGAACTG(p.Thr1042GlnfsTer75) variant causes a frameshift, missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.
ABCC8 (HGNC:59): (ATP binding cassette subfamily C member 8) The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the MRP subfamily which is involved in multi-drug resistance. This protein functions as a modulator of ATP-sensitive potassium channels and insulin release. Mutations in the ABCC8 gene and deficiencies in the encoded protein have been observed in patients with hyperinsulinemic hypoglycemia of infancy, an autosomal recessive disorder of unregulated and high insulin secretion. Mutations have also been associated with non-insulin-dependent diabetes mellitus type II, an autosomal dominant disease of defective insulin secretion. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Jul 2020]
Verdict is Pathogenic. Variant got 18 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 11-17406924-GGT-CAGTTCCTGGCTG is Pathogenic according to our data. Variant chr11-17406924-GGT-CAGTTCCTGGCTG is described in ClinVar as [Likely_pathogenic]. Clinvar id is 188894.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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not provided Pathogenic:1
Jan 17, 2019
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change creates a premature translational stop signal (p.Thr1042Glnfs*75) in the ABCC8 gene. It is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individuals affected with ABCC8-related conditions (PMID: 26740944, 17668386). This variant is also known as c.3127_3129delACCinsCAGCCAGGACCTG in the literature. ClinVar contains an entry for this variant (Variation ID: 188894). Loss-of-function variants in ABCC8 are known to be pathogenic (PMID: 20685672, 23345197). For these reasons, this variant has been classified as Pathogenic. -